Manufacture of sound-amplifying horns



Aug. 3,19 ze. 1,594,991

G. w. BULLEY MANUFACTURE OF SOUND'`AMPLIFYING HORNS Filed Feb. a'. 1926 [nnen/Zar:

Patented Aug. 3, 1926.

unirse stares 1,594,397 earner arriere,

GEORGE W. BULLEY, OF AKRON, OHO, ASSIGNOR TO THE .MLLER RUBBER COMPANY,

OF AKRON, OHIO, A GORLPORATON OF OHIO. i

`lVlAINUFACTURE OF SOUND-AMPLIFYING HORNS.

Application led February My presentinvention relates to improvements in sound amplifying horns such as are used for radio loud speakers and kindred purposes, and concerns particularly horns which are made of hard vulcanized rubber thouoh not limited in all it-s as Jects to a vulcanizing heat While at the same time expanded by fluid pressure supplied by the volatilization of a blowing agent inserted Within the biscuit, the pressure of the fluid from the blowing agent forcing the material against the Walls of the mold, Where it becomes vulcanized to the consistency of hard rubber.

In order to confine the gas in such an article during manufacture, it is necessari.7 to provide a blow-over at each end thereof, or in other Words, a closed end which must be removed after the molding of the article.

It is also necessary that the neck of the horn shall be provided With means for connection to the loud speaking device. The commercial types of loud speaking devices differ materially in size, which requires that the standard types and sizes of horn shall be manufactured each With large variations in the neck connections, Which neck connections must be rmly attached to the horns so that no air leaks take place at the point of connection to the loud speaking,` deviceL The present invention aims to provide a method and means whereby a metal ferrule may be rigidly attached to the neck of the horn during the manufacture in such a manner as to support the blow-over and retain the fluid pressure, and in which such blow-over may be readily bored out to secure the necessary air passage.

The invention aims further to provide a method and means whereby a horn of the standard type or size may ybe produced With means whereby it may be readily adapt-ed for connection With any one of the various sizes of standard loud speakers, thereby greatly reducing the amount of stock necessary to be produced and carried on hand.

With these and other objects in View,

- Fig'. l.

Serial No. 86,869.

the invention includes the novelI method anc article hereinafter described, and particularly defined in the appended claims.

ln order that my invention may be better understood, reference is made to the accompanying drawing, in Whichz* Figure l is a sectional vieiv through a horn member as it appears upon the completion of the vulcanization.

Figs. 2 and 2a are sectional vieivs illustrating` supplemental and interchangeable nipples for application thereto, and

F 3 is a sectional vieiv illustrating the boring out or" the blow-over.

It may be stated at this point that horns of large sine c Lstomaiily made in tivo sections for convenience in manufacture, due to complication in shape, these sections being-g' known respectively as the goose-neck and the bell, but for small horns the goose-neck, or a part equivalent thereto, Would sutlice, and for convenience of illustration I have sllovvn in the present drawing,` only the goose-neck part, which in the present dran.'- ing` is numbered l. Vfhile thel biscuit is in its plastic and unvulcanized condition, a ine-tal ferrule 2 is applied to the small end thereof, which metal fer-rule has a closed end and is provided with an inwardly swaged portion or portions for interlocking with the rubber neck for rigidly holding the ferrule in place, which interlock is preferably formed in the shape of an inwarc ly sWaged portion 2b which forms an internal annular rib and corresponding,T external annular groove. 'he closed end ivall 2nu cooperates in support-ing the blow-over forming material, which is indicated at la.

Preferably the closed end is provided With a central indentation al which serves to accurately center the boring bit hereinafter' referred to. The vulcanization of the horn in the manner described converts the rubber into hard rubber and causes the ferrule to be rigidly secured in the position shown in For cooperating with this ferrule 2 l provide a plurality of ferrules 3 Which have cylindrical parts 3a the interior diameter of Which accurately lits the external diameter of the ferrule 2, and which are provided With tubular extensions 3b of sizes corresponding to the various sizes or typesV of commercial loud speakers. Given an order or demand. for horns for attacnment to a loud speaker of a certain type, it 1s only necessary to pick from stock the requisite number of horns l and to assemble on these the terrules 3 of, the proper size. ucli terrule 3 having been slipped onto the ferrule 2, the sheet metal of the Wall 3 which lies over the channel 2b is spun down into the same either by hand or suitable ap` paratus, as shown in Fig. 3, interlocking 'the two iiimly together. Thereafter the closed end 2a and blow-over la are bored out by a suitable drill /l, the extension 3b serving as a guide for the drill.`

Having thus described my invention, what l claim is:-

l. The hereindescribed method of making amplifying horns which consists in forming a hollow biscuit of unvulcanized hard rubber with a contracted end, placing a nipple on said contracted ene, and subsequently vulcanizing the biscuit in a suitable mold While subjected to internal fluid pressure.

2. The hereindescribed method ot' making amplifying horns, Which consists in forming a hollow biscuit of unif'ulcanized hard rub` her having a contracted end, placing on said end a nipple having an inwardly extending projection on its inner surface, and subsequently ifulcanizing the biscuit in a suitable mold While subjected to internal fluid pres sure.

The hereind-escribed method of making amplifying horns which consists in forming a hollow biscuit oi unvulcanized hard rubber compound ii'itli a contracted end,' placing` about said end a nipple having a closed end, rulcanizing tliebiscuit in a suitable mold While subjected to internal fluid pressure, and iinally boring through the end of the nipple and the underlying layer of hard rubber.

el. The heieindescribed method or' inaliig amplifying horns which consists-in -orming a hollow biscuit et un'vulcanized rubber compound With a'contracted GEORGE lV. BULLEV.

id placing about said end a nipple having 

